Tamper evident container closures

ABSTRACT

Disclosed herein is a method and apparatus for closing a container ( 10 ) with a tamper evident closure ( 26 ) wherein the closure has a tamper evident ring ( 38 ) with driving features ( 52 ) that enable a given closure fitting tool ( 54 ) with driving features ( 60 ) complementary to those of the closure and the ring to be used to drive the closure and the ring onto the container neck ( 12 ) without exerting closing torque on the frangible links ( 40 ), the links may be made more readily frangible than heretofore; in an embodiment the ring driving features are one-way to prevent the tool from being used to open the container without breaking the links.

[0001] This invention relates to anti-tamper closures and itparticularly, but not exclusively, relates to closures having tamperevident features for blow-moulded containers.

[0002] A known tamper evident container closure comprises a containerhaving a neck in combination with a closure for the container neck, theneck and closure having rotatably interengaging features whereby theclosure can removeably close the neck and seal the container and acontinuous or segmented tamper evident ring attached by frangible linksto the closure, the ring and the container neck having complementaryone-way features that, in use, permit closing rotation of the closureand ring relative to the container but which interact to prevent openingrotation of the ring and thereby break the frangible links to providetamper indication. The closure and tamper evident ring are usuallyintegrally-formed of plastics by injection-moulding and the containernecks with the one-way features are either separate plastics mouldingswelded or other-wise attached to a container or the container is,preferably, a unitary plastics blow-moulding with all neck featuresbeing formed integrally with the container. Such 220 liter (55 gallon)containers are rapidly becoming a standard in many industries, includingcontainers for drink concentrates.

[0003] Documents EP-A-0 324 196; U.S. Pat. No. 4,308,969; DE-A-30 10769; U.S. Pat. No. 4,607,759 disclose examples of this type of tamperevident container closure. There are problems with this type ofcontainer closure. One problem is that the closure has to be fitted tothe container by relative rotation of the closure with the one-wayfeatures riding one over the other until the closure closes and sealsthe container neck, this exerts a significant closing torque or relativeturning force between the closure and the ring and the links have to bestrong enough to resist this force. These “strong enough” links areeither too strong for the closure to be readily removable or, moreimportantly, can permit the closure to be rotated off the containerwithout breaking the links; as the ring can ride backwards over theone-way features without breaking some or all of the links. Anotherproblem is that the fitting of closures to containers is oftenmechanised and the closing torque set for closure rotation, to ensure areliable seal between the closure and the neck of a blow-mouldedcontainer is often so high that the links can break on driving theclosure onto the container neck.

[0004] The present invention provides a solution to the above-statedproblems.

[0005] According to the present invention, a method of fitting a tamperevident container closure to the neck of a container comprises the stepsof:

[0006] i) providing rotatably interengaging features on the containerneck and closure by which the closure can removeably close the neck andseal the container;

[0007] ii) attaching a continuous or segmented tamper evident ring byfrangible links to the closure;

[0008] iii) providing complementary one-way features on the ring and thecontainer neck that, in use, permit closing rotation of the closurerelative to the container but which interact to prevent opening rotationand thereby break the frangible links;

[0009] iv) providing the closure and the tamper evident ring withdriving features;

[0010] v) providing a closure fitting tool with driving featurescomplementary to those of the closure and the ring;

[0011] vi) loading the fitting tool with a closure;

[0012] vii) offering the tool to a container neck; and,

[0013] viii) rotating the tool with respect to the container to drivethe closure and the ring onto the neck.

[0014] By this means, the closure tool effectively bridges the frangiblelinks and exerts closing torque directly on the tamper evident ring aswell as on the closure such that the links can be more readily frangibleas they do not have to transmit closing torque from the closure to thering.

[0015] It is known to provide a tamper evident container closure with adriven tamper evident ring in the form of a one-way feature dependingfrom the closure and engaging a complementary one-way feature of thering. Not only is such a closure more difficult to mould than a closurefor the method of the present invention but the complementary one-waydriving features can make the closure difficult to undo.

[0016] In an embodiment of the method of the present invention, thecomplementary tamper evident ring is provided with one-way drivingfeatures, to thereby prevent rotation of the tool in the openingdirection from driving the tamper evident ring. This prevents a closingtool being used to open a container without breaking the frangiblelinks.

[0017] Also according to the present invention, a tamper evidentcontainer closure for a container having a neck, wherein:

[0018] i) the closure and a given container neck have rotatablyinterengaging features whereby, in use, the closure can removeably closethe neck and seal the container;

[0019] ii) the closure has a continuous or segmented tamper evident ringattached thereto by frangible links;

[0020] iii) the ring and the container neck have complementary one-wayfeatures that, in use, permit closing rotation of the closure relativeto the container but which interact to prevent opening rotation andthereby break the frangible links; and,

[0021] iv) the closure and the ring have driving features, such that agiven closure fitting tool with driving features complementary to thoseof the closure and the ring may be used to drive the closure and thering onto the neck.

[0022] According to an embodiment of the present invention, thecomplementary tamper evident ring and tool driving features are one-way;whereby rotation of the tool in the opening direction will not drive thetamper evident ring.

[0023] The above and other features of the present invention areillustrated, by way of example, in the Drawings, wherein:

[0024]FIG. 1 is a part-sectioned elevation of a tamper evident containerclosure in a container neck and in accordance with a first embodiment ofthe present invention;

[0025]FIG. 2 is a plan of the closure of FIG. 1;

[0026]FIG. 3 is a part underplan of the closure of FIG. 1;

[0027]FIG. 4 is an enlarged detail of the closure of FIG. 1;

[0028]FIG. 5 is a sectional elevation of a closure fitting tool forclosure of FIG. 1;

[0029]FIG. 6 is an enlarged detail of the closure fitting tool of FIG.5;

[0030]FIG. 7 is an underplan of the closure fitting tool of FIG. 5;

[0031]FIG. 8 is a plan of a closure opening tool for the closure of FIG.1;

[0032]FIG. 9 is an elevation of the closure opening tool of FIG. 8;

[0033]FIG. 10 is a part-sectioned elevation of a tamper evidentcontainer closure in accordance with a second embodiment of the presentinvention; and,

[0034]FIG. 11 is an underplan of the closure of FIG. 10.

[0035] As shown by FIG. 1, a container 10, which may be a 220 liter drumblow-moulded from plastics material, such as HDPE high densitypolyethylene, has a neck 12 located the upper surface 14 of the drum.

[0036] The integrally moulded neck 12 projects both axially outwardlyfrom the recessed drum surface 14 and axially inwardly into the drum.The neck 12 has a rim 16, an internal thread 18 and a radially inwardlydirected flange 20 located axially inwards of the screw thread 18.Flange 20 has an axially outwardly directed, frusto-conically shapedsealing counterface 22. A series of radially outwardly extending,anti-tamper ratchet teeth 24 are formed about the axially outwardlyextending part of the neck 12.

[0037] As shown by FIGS. 1 to 4, a closure cap 26 is moulded fromplastics material, such as PE polyethylene or PP polypropylene, to havea generally axially cylindrical body 28 with a thread 30 formed on theexterior surface thereof. A radial peripheral groove 32 is located underthe cap screw thread 30. The cap top 34 has a radially outwardlyextending flange, the underside of which has an axial groove 36 ofcomplementary cross-section to the container neck rim 16. An annulartamper evident ring 38 is connected to the cap top 34 by axial frangiblelinks 40. The inner surface of the anti-tamper ring 38 is provided withradially inwardly extending anti-tamper ratchet teeth 42 which are, inknown manner, shaped to pass over container neck anti-tamper ratchetteeth 24 when the cap 26 is rotated into the neck 12, but to interlocktherewith when the cap is rotated out of the neck, to break the links 40and provide anti-tamper indication. The anti-tamper ring 38 is mouldedwith the cap 26.

[0038] A sealing ring 44 of generally rectangular or round cross-sectionis located in the cap radial groove 32.

[0039] The exterior of the closure cap 26 is designed to avoid anyrecesses or cavities which might retain and later contaminate drumcontents.

[0040] The outer peripheral rim 46 of the cap top 34 and the outerperipheral rim 48 of the tamper evident ring 38 are castellated at 50and 52 for ready engagement by the metal head 54 of an automatic capfitting and closing tool (FIGS. 5 to 7), the head is shaped to engageboth the cap and the ring to ensure that the links 40 are notinadvertently broken as the cap is being screwed onto the neck.

[0041] As shown more clearly in FIGS. 3 and 4, the cap top castellations50 and the tamper evident ring castellations 52 form driving features,having axially aligned leading radial edges 56 and 58 that are picked upby radially inwardly directed axial spines 60 of the cap fitting tool54; the inner depth of the cap fitting tool being sufficient to engageboth castellations 50 and 52 when the cap is loaded into the tool. Whenused to fit a cap 26 to a container neck 12, the tool will drivedirectly both the cap and the tamper evident ring 38 so that no closingtorque is imparted to the frangible links 40.

[0042] Whilst the cap castellations 50 are shown to be conventionallyrectangular, to serve both as closing driving features and subsequentopening features, the tamper evident ring castellations 52 are shown tobe wedge- or cam-shaped, tapering radially inwardly from the leadingedge 58 into the ring peripheral rim 48. This shape enables these tamperevident ring castellations 52 to have a one-way driving effect; whilstthe cap fitting tool splines 60 can pick up and drive the tamper evidentring castellations 52 in the closing direction they will ride over thecastellations when the tool is turned in the reverse, opening direction.Thus no opening driving action can be exerted by the tool on the tamperevident ring, it can only exert an opening driving action on the capcastellations 50, consequently opening torque will be transmitted to andbreak the frangible links 40.

[0043] Additionally, the tamper evident ring anti-tamper ratchet teeth42 are shown to be vanes trailing radially inwards and in the capclosing rotational direction, the vane free ends 62 riding over thecontainer neck ratchet teeth 24 when the cap 26 is rotated in theclosing direction but locking against the container neck ratchet teeth24 when the cap is rotated in the opening direction. The vanes permitthe tamper evident ring 38 to flex radially inwardly and thus break thefrangible links 40 if an attempt to open the container 10 is made by useof a cap fitting tool 54. This action being in addition to transmissionof container opening torque to the frangible links 40 described in theprevious paragraph.

[0044] The container 10 can be opened by the use of the opening tool 64shown in FIGS. 8 and 9. The tool has a handle 66 and a ring 68 having adiameter to pass over a cap 26 and radially inwardly directedcastellations 70 about the inner periphery 72 of the ring, the inner andcastellations being complimentary in shape to the cap peripheral rim 46and cap castellations 50. The opening tool is required because of thehigh closing torque exerted on the cap by the automating closingmachinery.

[0045] A second embodiment of a tamper evident closure cap in accordancewith the present invention is shown by FIGS. 10 and 11. In thisembodiment, a DIN 60 type screw closure cap 74, being a HDPE highdensity polyethylene moulding of generally known type, has wedge- orcam-shaped, one-way driving features 76 formed in the peripheral rim 78of the tamper evident ring 80. Anti-tamper vanes 82 are formed in theinner periphery 84 of the tamper evident ring 80, which is joined to thecap 74 by radial frangible links 86. The cap 74 has a series of radiallyoutwardly and axially extending ribs 88 equispaced about the capperiphery 90 and which constitute cap driving features. These drivingfeatures 76 and 88 are not axially aligned; unlike the cap and ringdriving features 50 and 52 of the first embodiment.

1. A method of fitting a tamper evident container closure to the neck ofa container comprising the steps of: i) providing rotatablyinterengaging features (18, 30) on the container neck (12) and closure(26, 74) by which the closure can removeably close the neck and seal thecontainer (10); ii) attaching a continuous or segmented tamper evidentring (38, 80) by frangible links (40, 86) to the closure; iii) providingcomplementary one-way features (24, 42, 82) on the ring and thecontainer neck that, in use, permit closing rotation of the closurerelative to the container but which interact to prevent opening rotationand thereby break the frangible links; iv) providing the closure (50,88) with driving features; v) providing a closure fitting tool (54) withdriving features (60) complementary to those of the closure; vi) loadingthe fitting tool with a closure; vii) offering the tool to a containerneck; and, viii) rotating the tool with respect to the container todrive the closure onto the neck; characterised in that it comprises thefurther steps of: ix) providing the tamper evident ring (38, 78) withdriving features (52, 76); x) providing the closure fitting tool (54)with driving features (60) complementary to those of the ring; and, xi)rotating the tool with respect to the container (10) to drive theclosure (26) and the ring onto the neck (12).
 2. A method as claimed inclaim 1 and further characterised by the step of providing one-waytamper evident ring driving features (52, 76), to thereby preventrotation of the tool (54) in the opening direction from driving thetamper evident ring.
 3. A tamper evident container closure for acontainer having a neck, wherein: i) the closure (26, 74) and a givencontainer neck (12) have rotatably interengaging features (18, 30)whereby, in use, the closure can removeably close the neck and seal thecontainer (10); ii) the closure has a continuous or segmented tamperevident ring (38, 80) attached thereto by frangible links (40, 86); iii)the ring and the container neck have complementary one-way features (24,42, 82) that, in use, permit closing rotation of the closure relative tothe container but which interact to prevent opening rotation and therebybreak the frangible links; and, iv) the closure has driving features(50, 88), such that a given closure fitting tool (54) with drivingfeatures (60) complementary to those of the closure may be used to drivethe closure onto the neck; characterised in that v) the tamper evidentring (38, 78) has driving features (52, 76), such that a given closurefitting tool (54) with driving features (60) complementary to those ofthe closure (26, 74) and the ring may be used to drive the closure andthe ring onto the neck (12).
 4. A closure as claimed in claim 3 andfurther characterised in that the complementary tamper evident ringdriving features (52, 76) are one-way; whereby rotation of the tool (54)in the opening direction will not drive the tamper evident ring.
 5. Aclosure as claimed in claim 3 and further characterised in that theclosure is a cap (26), the outer peripheral rim (46) of the cap top (34)and the outer peripheral rim (48) of the tamper evident ring (38) arecastellated at (50) and (52) for engagement by an automatic cap fittingand closing tool (54) that is shaped to engage both the cap and the ringto ensure that the links (40) are not inadvertently broken as the cap isbeing screwed onto the neck.
 6. A closure as claimed in claim 4 andfurther characterised in that the tamper evident ring is flexible (38,78) and the one-way ring driving features (52, 76) are arranged so thatan attempt to open the container (10) by use of a closure fitting tool(54) would cause the ring to flex radially inwardly by engagementbetween the one-way ring driving features and the closure fitting tooldriving feature (60) to break the frangible links (40, 86).
 7. A closureas claimed in claim 6 and further characterised in that the tamperevident ring one-way driving features are vanes (42, 82) arranged totrail radially inwards and in the closure closing direction of rotation,the vanes permitting the tamper evident ring (38, 80) to flex radiallyinwardly when the closure fitting tool (54) is rotated in the openingdirection.